Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
Brittle, UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
Ca 9(Mg,Fe2+ )(PO 4) 6(PO 3OH)Anthony et al , Handbook of mineralogy (2001)
(Mg,Fe)Al 3(BO 4)(SiO 4)OUlrich Henn and Claudio C.